It has already been known that certan platinum complexes have a carcinostatic effect [e.g., Journal of Pharmaceutical Sciences, Vol. 65, No. 3, 315-328 (1976) and Journal of Inorganic Biochemistry, 11, 139-149 (1979)].
Among these compounds, cis-dichlorodiammineplatinum (cis-Platin, generic name) has a very excellent carcinostatic effect and is now widely used as clinical medicine. However, this compound is disadvantageous in that it is high in toxicity, particularly in renal toxicity and is very low in water-solubility.